72 ON THE ORIGIN OF SPECIES 



imagination to give the plant the power of increasing in 

 number, we should have to give it some advantage over 

 its competitors, or over the animals which preyed on it. 

 On the confines of its geographical range, a change of 

 constitution with respect to climate would clearly be an 

 advantage to our plant ; but we have reason to believe 

 that only a few plants or animals range so far, that they 

 are destroyed by the rigour of the climate alone. Not 

 until we reach the extreme confines of life, in the 

 Arctic regions or on the borders of an utter desert, will 

 competition cease. The land may be extremely cold or 

 dry, yet there will be competition between some few 

 species, or between the individuals of the same species, 

 for the warmest or dampest spots. 



Hence, also, we can see that when a plant or animal 

 is placed in a new country amongst new competitors, 

 though the climate may be exactly the same as in 

 its former home, yet the conditions of its life will 

 generally be changed in an essential manner. If we 

 wished to increase its average numbers in its new home, 

 we should have to modify it in a different way to what 

 we should have done in its native country ; for we 

 should have to give it some advantage over a different 

 set of competitors or enemies. 



It is good thus to try in our imagination to give any 

 form some advantage over another. Probably in no 

 single instance should we know what to do, so as to 

 succeed. It will convince us of our ignorance on the 

 mutual relations of all organic beings ; a conviction as 

 necessary, as it seems to be difficult to acquire. All 

 that we can do, is to keep steadily in mind that each 

 organic being is striving to increase at a geometrical 

 ratio ; that each at some period of its life, during some 

 season of the year, during each generation or at 

 intervals, has to struggle for life, and to suffer great 

 destruction. When we reflect on this struggle, we may 

 console ourselves with the full belief, that the war of 

 nature is not incessant, that no fear is felt, that death 

 is generally prompt, and that the vigorous, the healthy, 

 and the happy survive and multiply. 



